Heating element for roads and the like



@Qt 24, 1967 mugo s 3,349,225

HEATING ELEMENT FOR ROADS AND THE LIKE Filed May 3, 1.965

United States Patent Ofifice 3,349,225 HEATING ELEMENT FOR ROADS AND THE LIKE Robert Dubois, Prilly, Vaud, Switzerland, assignor to Colfico, S.A., Sion, Valais, Switzerland Filed May 3, 1965, Ser. No. 452,507 Claims priority, application Switzerland, May 4, 1964, 5,812/ 64; Nov. 2, 1964, 14,143/64 1 Claim. (Cl. 219-545) ABSTRACT OF THE DISCLOSURE In combination with a heating coat for a road or wall surface including a first layer of synthetic resin laid on the surface, a second covering layer of synthetic resin, a heating element between the first and second layers, the element consisting of at least one layer of fabric woven with threads of glass fibres and wires adapted to be electrically incorporated with said fabric and extending partly weft threads and partly along the warp threads of the fabric and means electrically insulating at their crossing points the heating wires extending along the warp with reference to the wires extending along the weft threads, the wires being spaced by 20 to 30 mm.

My invention has for its object a heating element adapted chiefly for incorporation with the coat covering a road or wall.

Heated roads have already been proposed which are provided with a number of pipes arranged underneath their tread surface and through which steam or hot water is caused to flow.

Such a type of road has however not been executed on a very large scale, on one hand by reason of the roads is far from being rentable.

My improved heating element has now for its object to remove these drawbacks and it is characterized to this end by the fact that it includes a woven fabric made of synthetic material or of glass fibre-incorporating resistance wires forming the actual heating body of the element.

My improved heating element is intended for incorpopreferred embodiment, the wires are partly along the warp threads of the executed in situ by covering first the of synthetic resin with the interposition, if required, of a heat-insulating material or otherwise, laying over of synthetic resin a heating body and covering said heating body with a further layer of synthetic resin. Such operative steps, if they are to be economical, should be performed on comparatively long areas.

The heating element according to my invention may, for instance, be constituted by a piece of woven fabric 3,349,225 Patented Oct. 24, 1967 of a length equal to 10, 15 or 20 meters, which may be brought onto the building site as a roll which is unwound gradually as it is being applied over the road. Said piece of fabric may, if required, be connected endwise with a further similar piece of fabric through any suitable mechanical means. Similarly, the heating Wires incorpo rated with it, may be connected endwise with the corresponding .wires of the immediately adjacent pieces of fabric.

Of course, my improved heating element may also be executed in the shape of smaller sections brought in a fiat condition in suitable packages, to the point at which it is to be used, chiefly when the heating wires have a comparatively large diameter or the size of the building site does not allow in practice the use of pieces of fabric wound into rolls. This is the case, for instance, each time it is desired to lay a heating coat on sidewalks, staircases, vertical walls and the like.

Numerous other applications of my invention are also possible. Thus, the heating element may be simply constituted by a heating fabric adapted for use in the execution of garments, furniture or carpets. Generally speaking, its features are such that it is light, resists comparatively large mechanical stresses, and may be executed in a cheap manner, while it resists the action of various chemical reagents and supplies a large therrnic energy.

The woven fabric carrying the electric heating wires is made of glass fibres or, according to a modification, of synthetic material say threads made of nylon, a polyester or the like. Said fabric may be obtained in a conventional manner on a loom or be formed directly through extrusion of the fibres. It is also possible to obtain the fabric through the superposition of two series of parallel threads extending in orthogonal directions, with a gluing or welding of the threads of said series at their crossing points.

Fabric in accordance with the invention is illustrated schematically in the accompanying drawings in which:

FIG. 1 is a schematic perspective view of a portion of a heating element in accordance with the invention.

FIG. 2 is a cross section of the heating element shown in FIG. 1 taken approximately on the line IIII of FIG. 1.

FIG. 3 is a schematic another embodiment.

In the drawings, the fabric body has been shown in phantom as it can be of any desired construction. In the embodiment illustrated in FIGS. 1 and 2, two groups of heating wires 2 and 3 are incorporated in the fabric body 1 of glass fibre. The heating wires of each group are parallel to one another and are woven into the fabric. As will be seen from FIG. 2, the wires of groups 2 and 3 are separated from one another at their crossing points and are thus electrically insulated from one another at such points. The wires of group 3 have extremities 7, 8 connected to an electrical source of energy and wires of group 2 have their extremities 5, 6 connected to an electrical source of energy.

In FIG. 3 there is shown another embodiment in which there is only a single series of parallel wires 2a incorporated in the woven fabric body 1a. The wires 2a may extend in either a warpwise or in a weftWise direction. Although they have been shown schematically as being straight, they are woven into the fabric. Their extremities 9, 10 are connected to an electrical source of energy.

Suitable electrical connections (not shown) are provided for connecting the heating wires in series, or in parallel or partially in parallel, into an electrical circuit to supply electrical current. It will further be understood that switches, transformers, rheostats or other suitable perspective view of a portion of control means are provided for controlling the current supplied to the heating wires incorporated in the fabric, for example in accordance with the heat required to maintain a selected temperature.

The different wires incorporated with the Warp threads of the piece of woven fabric, may be spaced from each other by 20 or 30 mm. according to the case. The metal forming such wires may be copper, aluminium or even steel. Said metal wires may in fact replace at intervals some of the warp threads or else some of the weft threads of the fabric. It is also possible to insert electric leads between the warp or weft threads or to set them across the latter. In the case of fabrics including a plurality of layers of synthetic fibres, it will be readily understood that the wires may be superposed in a similar manner.

When the piece of woven fabric shows wires both along the warp and along the weft, suitable means is provided for the electric insulation between said wires at their crossing points.

What I claim is:

In combination with a heating coat for a road or wall surface including a first layer of synthetic resin laid on a said surface, a second layer of synthetic resin, a heating element between said first and second layers, said element consisting of at least one layer of fabric w-oven of threads of glass fibres and wires adapted to be heated electrically incorporated with said fabric and extending partly along the weft threads and partly along the warp threads of the fabric and means electrically insulating at their crossing points the heating wires extending along the warp with reference to the wires extending along the weft threads, said wires being spaced by 20 to 30 mm.

References Cited UNITED STATES PATENTS 1,036,632 8/1912 Jahr 219-545 X 1,456,223 5/ 1923 Craddick et al. 219-212 X 2,385,577 9/1945 Jacob 338-208 2,439,892 4/ 1948 Huck 219-529 2,706,768 4/1955 Kaplan 219-528 X 2,732,479 1/1956 Rowland 219-529 X 2,862,097 11/1958 Negrornanti 219-545 X 2,884,509 4/1959 Heath 219-545 X 2,938,992 5/1960 Crurnp 219-545 X 3,064,332 11/1962 Kaplan 219-529 X 3,288,912 11/1966 Hussey 174-70 FOREIGN PATENTS 758,935 10/1956 Great Britain.

RICHARD M. WOOD, Primary Examiner.

VOLODYMYR Y. MAYEWSKY, Examiner. 

